  <developerConceptualDocument
      xmlns="http://ddue.schemas.microsoft.com/authoring/2003/5"
      xmlns:xlink="http://www.w3.org/1999/xlink">

    <introduction>
      <para>This add-in allows you to create first class functions in Excel. Excel
      is a purely functional language, aside from macros, but there is no native facility
      for creating functions within Excel other than VBA or the Excel SDK for
      creating user defined functions using C/C++.
      </para>
    </introduction>
    <section>
      <title>Theory</title>
      <content>
        <para>
          Let <math>T</math> be a type and <math>
          f:T<superscript>n</superscript> &#8594; T</math> be a function. Define 
          <blockQuote>bind:<math>
          (T<superscript>n</superscript> &#8594; T) &#215; T<superscript>?n</superscript>
          &#8594; T<superscript>n - ?</superscript>
        </math>
          </blockQuote>
        </para>
       </content>
      </section>
  </developerConceptualDocument>

